Horizontal articulated robot and method for manufacturing horizontal articulated robot

ABSTRACT

A horizontal articulated robot in which an arm moves in the horizontal direction for use with objects to be transferred may include a hand on which the objects are to be mounted. The arm may have at least two arm portions including a hand-side arm portion to which the hand is rotatably joined to the front end thereof; and a second hand-side arm portion to which the base end of the hand-side arm portion is rotatably joined to the front end thereof; and a main body portion to which the base end of the arm is rotatably joined. A level which may be attached to the hand, the arm or the main body portion after an inclination of a center axis of rotation of the hand-side arm portion with respect to the second hand-side arm portion is adjusted relative to the vertical direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. national stage of application No. PCT/JP2014/070736,filed on Aug. 6, 2014. Priority under 35 U.S.C. § 119(a) and 35 U.S.C. §365(b) is claimed from Japanese Applications Nos. 2013-247026, filedNov. 29, 2013; and 2013-247029, filed Nov. 29, 2013; the disclosures ofwhich are incorporated herein by reference. Priority is also claimedunder 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.61/864,272, filed Aug. 9, 2013, the disclosure of which is incorporatedherein by reference.

FIELD OF THE INVENTION

At least an embodiment of the present invention relates to a horizontalarticulated robot with an arm which moves in the horizontal direction,and a method for manufacturing the horizontal articulated robot.

BACKGROUND

Conventionally known is a horizontal articulated robot which configurespart of an EFEM (Equipment Front End Module) and which transferssemiconductor wafers between a FOUP (or multiple FOUPs) and asemiconductor wafer processing apparatus (Patent reference 1, forexample). The industrial robot disclosed in Patent reference 1 isprovided with two hands on which semiconductor wafers are to be mounted,an arm, to which the two hands are rotatably joined to the front endthereof, and a main body portion, to which the base end of the arm isrotatably joined. The arm is configured by a first arm, of which thebase end is rotatably joined to the main body portion, a second arm, ofwhich the base end is rotatably joined to the front end of the firstarm, and a third arm, of which the base end is rotatably joined to thefront end of the second arm and to which the hands are rotatably joinedto the front end thereof. An arm-elevating mechanism is housed insidethe main body portion to raise and lower the first arm.

Also, known as a vertical articulated robot is one equipped with a base,a body fixed to the base, a first arm which is rotatably joined to thebody, a second arm which is rotatably joined to the first arm, a wristwhich is rotabaly joined to the second arm, and fingers which arerotatably joined to the wrist (see Patent reference 2, for example). Inthe vertical articulated robot disclosed in Patent reference 2, a levelfor adjusting the original position is attached to the first arm and thefingers.

Also, conventionally known is a horizontal articulated robot fortransferring semiconductor wafers (see Patent reference 1, for example).A horizontal articulated robot disclosed in Patent reference 3 isequipped with a hand on which semiconductor wafers are to be mounted, anarm to which the hand is rotatably joined to the front end thereof, anda base to which the base end of the arm is rotatably joined. The arm isconfigured by a first arm portion, of which the base end is rotatablyjoined to the base, and a second arm, of which the base end is rotatablyjoined to the front end of the first arm portion and to which the handis rotatably joined to the front end thereof.

In the horizontal articulated robot disclosed in Patent reference 3, aturning drive means is equipped to rotate the second arm portion withrespect to the first arm portion. The turning drive means is providedwith a motor which is arranged inside the first arm portion such thatthe axial direction of the output shaft coincides with the horizontaldirection, a first bevel gear which is coupled with the output shaft ofthe motor, a second bevel gear which meshes with the first bevel gear, athird gear which is formed at the bottom end of a cylindrical protrusionsecured to the base end of the second arm portion, and a second gearwhich meshes with the third gear and is formed integrally with thesecond bevel gear.

PATENT REFERENCE

[Patent reference 1] Unexamined Japanese Patent Application Publication2011-230256

[Patent reference 2] Unexamined Utility Model Application Publication63-147704

[Patent reference 3] Unexamined Japanese Patent Application Publication2008-264980

A FOUP is manufactured based on a SEMI (Semiconductor Equipment andMaterials Institute) standard; multiple semiconductor wafers are storedin a FOUP such that they are superposed at a fixed pitch in the up-downdirection. A gap is created between multiple semiconductor wafers storedin the FOUP, and the gap is relatively small. A horizontal articulatedrobot which transfers semiconductor wafers between a FOUP and asemiconductor wafer processing apparatus needs to put its hand in thesmall gap between the multiple semiconductor wafers stored in the FOUP,mounts a semiconductor wafer on the hand and takes it out of the FOUP.Therefore, the horizontal articulated robot needs to be preciselyinstalled so that the hand precisely moves in the horizontal direction.

In general, to precisely install the horizontal articulated robot, theinclination of the hand or the like is studied in its every state, suchas the state where the arm is extended in a certain direction, the statewhere the arm is extended in the other direction and the state where thearm is retracted, by using a level at the time of the installation ofthe horizontal articulated robot while changing the states of thehorizontal articulated robot so that the hand can make optimal movementsin the horizontal direction. For this reason, it takes time to installthe horizontal articulated robot which transfers semiconductor wafers.Also, since the inside of the EFEM housing in which the horizontalarticulated robot is housed is not very spacious, the work of installingthe horizontal articulated robot is difficult.

SUMMARY

Therefore, at least an embodiment of the present invention provides ahorizontal articulated robot with an arm moving in the horizontaldirection, which can be installed such that a hand can make precisemovements in the horizontal direction with ease in a short amount oftime. Also, at least an embodiment of the present invention provides amethod for manufacturing a horizontal articulated robot having an arm tomove in the horizontal direction, which can be installed such that ahand can make precise movements in the horizontal direction with ease ina short amount of time.

Next, in the horizontal articulated robot disclosed in Patent reference3, a motor is arranged inside the first arm portion such that the axialdirection of the output shaft coincides with the horizontal direction;therefore, even when a motor is arranged inside the first arm portion,the first arm portion can be made thin. However, in this horizontalarticulated robot, the power force of the motor which configures aturning drive means is transmitted to the second arm portion via a firstbevel gear, a second bevel gear, a second gear and a third gear;therefore, it is difficult to increase the reduction ratio in thepower-transmitting path from the motor to the second arm portion.Therefore, in this horizontal articulated robot, a motor having a largeoutput needs to be used for the motor configuring the turning drivemeans, thus increasing the size of the motor. Also, in this horizontalarticulated robot, the power force of the motor is transmitted to thesecond arm portion via the first bevel gear, the second bevel gear, thesecond gear and the third gear, therefore, this increases backlash inthe power-transmitting path from the motor to the second arm portion.

Therefore, at least an embodiment of the present invention provides ahorizontal articulated robot having a motor inside an arm portion thatconfigures part of an arm, the motor being positioned such that theaxial direction of its output shaft coincides with the horizontaldirection, capable of reducing the size of the motor and reducingbacklash.

To achieve the above, a horizontal articulated robot of at least anembodiment of the present invention having an arm that moves in thehorizontal direction comprises a hand on which objects-to-be-transferredare to be mounted, and an arm configured by at least two arm portions, ahand-side arm portion to which the hand is rotatably joined to the frontend thereof and a second hand-side arm portion to which the base end ofthe hand-side arm portion is rotatably joined to the front end thereof,a main body portion to which the base end of the arm is rotatablyjoined; wherein after the inclination of the center axis of rotation ofthe hand-side arm portion relative to the second hand-side arm portionis adjusted with respect to the vertical direction, a level is attachedto the hand, the arm or the main body portion.

Also, to achieve the above, a method for manufacturing a horizontalarticulated robot of at least an embodiment of the present invention isa method for manufacturing a horizontal articulated robot whichcomprises a hand, on which objects-to-be-transferred are to be mounted,an arm configured by at least two arm portions, that are a hand-side armportion which the hand is rotatably joined to the front end thereof anda second hand-side arm portion which the base end of the hand-side armportion is rotatably joined to the front end thereof, a main bodyportion to which the base end of the arm is rotatably joined, and alevel which is attached to the hand, the arm or the main body portion;wherein the level is attached after the inclination of the center axisof rotation of the hand-side arm portion relative to the secondhand-side arm portion is adjusted with respect to the verticaldirection.

The horizontal articulated robot of at least an embodiment of thepresent invention is equipped with a hand on whichobjects-to-be-transferred are to be mounted, a hand-side arm portion towhich the hand is rotatably joined, a second hand-side arm portion towhich the hand-side arm portion is rotatably joined, and a level whichis attached to the hand, the arm or the main body portion after theinclination of the center axis of rotation of the hand-side arm portionrelative to the second hand-side arm portion is adjusted with respect tothe vertical direction. Also, in a method for manufacturing a horizontalarticulated robot of at least an embodiment of the present invention, alevel is attached to the hand, the arm or the main body portion after atleast the inclination of the center axis of rotation of the hand-sidearm portion relative to the second hand-side arm portion is adjustedwith respect to the vertical direction.

Therefore, in at least an embodiment of the present invention, bypositioning the horizontal articulated robot in such that a levelattached to the horizontal articulated robot indicates a predeterminedcondition, the horizontal articulated robot can be installed such thatthe inclination of the center axis of rotation of the hand-side armportion, to which the hand is rotatably joined, with respect to thesecond hand-side arm portion is an appropriate inclination with respectto the vertical direction and the inclination of the hand is anappropriate inclination with respect to the horizontal direction.Therefore, in at least an embodiment of the present invention, thehorizontal articulated robot can be installed so that the hand makesprecise movements in the horizontal direction with ease with relativelysmall amount of time, compared to the above-described conventionalmethod for manufacturing a horizontal articulated robot.

In at least an embodiment of the present invention, it is preferred thata mounting face on which objects-to-be-mounted are to be mounted beformed to the hand and the level be attached after the inclination ofthe mounting face is adjusted with respect to the horizontal direction.With this configuration, by positioning the horizontal articulated robotin such a way that the level attached to the horizontal articulatedrobot indicates a predetermined condition, the horizontal articulatedrobot can be installed so that the hand can make more precise movementsin the horizontal direction.

In at least an embodiment of the present invention, the level is abubble tube-type level with a bubble tube, and after at least theinclination of the center axis of rotation of the hand-side arm portionwith respect to the second hand-side arm portion is adjusted withrespect to the vertical direction, the level is attached such that abubble inside the bubble tube is contained within the reference lineprinted on the tube. In this case, by positioning the horizontalarticulated robot in such a way that the bubble inside the bubble tubeof the level are contained within the reference line, the horizontalarticulated robot can be installed such that the inclination of thecenter axis of rotation of the hand-side arm portion with respect to thesecond hand-side arm portion is appropriate with respect to the verticaldirection and the inclination of the hand is appropriate with respect tothe horizontal direction.

In at least an embodiment of the present invention, it is preferred thatthe level be attached to the main body portion. In case the level is abubble tube-type level, if the level is attached to the arm or the hand,the bubble inside the bubble tube is easily displaced according to theextended/retracted condition of the arm; therefore, even if thehorizontal articulated robot is positioned such that the bubble iscontained within the reference line, the horizontal articulated robotmay not be installed such that the inclination of the hand with respectto the horizontal direction is an appropriate inclination, depending onthe extended or retracted condition of the arm at the time ofinstallation. On the other hand, when the level is attached to the mainbody portion, the bubble inside the bubble tube is rarely displaced evenwhen the arm changes its extended/retracted position; therefore, bypositioning the horizontal articulated robot such that the bubble iscontained within the reference line, the horizontal articulated robotcan be installed in such a way that the inclination of the hand withrespect to the horizontal direction is an appropriate inclinationregardless of the extended or retracted condition of the arm at the timeof installation.

Next, to achieve the above, the horizontal articulated robot with an armwhich moves in the horizontal direction, of at least an embodiment ofthe present invention, comprises a hand on whichobjects-to-be-transferred are to be mounted, an arm which is configuredby at least two arm portions, namely, a supporting-arm portion and asupported-arm portion which are relatively rotatably connected to eachother and to which the hand is rotatably joined, a main body portion towhich the base end of the arm is rotatably joined, and a rotationmechanism for rotating the supported-arm portion with respect to thesupporting-arm portion; wherein the rotation mechanism has a motor whichis arranged inside the supporting-arm portion or the supported-armportion such that the axial direction of the output shaft is in thehorizontal direction, a Harmonic Drive (registered trade mark) whichconfigures a joint, which is a joining portion between thesupporting-arm portion and the supported-arm portion, and which reducesthe power of the motor and transmits the result to the supporting-armportion or the supported-arm portion, a first bevel gear coupled withthe output shaft of the motor, and a second bevel gear which is coupledwith a wave generator of the Harmonic Drive (registered trade mark) andmeshes with the first bevel gear.

In the horizontal articulated robot of at least an embodiment of thepresent invention, the power force of the motor is reduced by theHarmonic Drive (registered trade mark) and transmitted to thesupporting-arm portion or the supported-arm portion. Therefore, it ispossible in at least an embodiment of the present invention that thereduction ratio is increased in the power transmitting path from themotor to the supporting-arm portion or the supported-arm portion.Accordingly, in at least an embodiment of the present invention, even ifa motor with small output is used, the supported-arm portion can berotated relative to the supporting-arm portion; as a result, the size ofthe motor can be reduced. Also, in at least an embodiment of the presentinvention, the power force of the motor is reduced by the Harmonic Drive(registered trade mark) and transmitted to the supporting-arm portion orthe supported-arm portion; therefore, backlash can be reduced in thepower transmitting path from the motor to the supporting-arm portion orthe supported-arm portion.

In at least an embodiment of the present invention, the arm isconfigured by arm portions, namely, a first arm portion, of which thebase end is rotatably joined to the main body portion, and a second armportion as a supporting-arm portion, of which the base end is rotatablyjoined to the front end of the first arm portion, and a third armportion as a supported-arm portion, of which the base end is rotatablyjoined to the front end of the second arm portion; the hand is rotatablyjoined to the front end of the third arm portion.

In at least an embodiment of the present invention, it is preferred thatthe horizontal articulated robot be provided with a first hand and asecond hand as a hand, which overlap in the up-down direction, a firstrotation mechanism for rotating the first hand with respect to the thirdarm portion, and a second hand rotation mechanism for rotating thesecond hand with respect to the third arm portion; the first handrotation mechanism be provided with a motor for the first hand arrangedinside the third arm portion and the second hand rotation mechanism beprovided with a motor for the second hand arranged inside the third arm;the first hand be provided with a joining portion which is joined to thethird arm portion and a flat mounting portion on whichobjects-to-be-transferred are to be mounted, and be positioned below thesecond hand; the mounting portion be formed extending in the horizontaldirection from the top edge of the joining portion, a protrusion portionprotruding upwardly be formed to the third arm portion; the protrusionportion be formed at the position shifted from the joining portion inthe longitudinal direction of the third arm portion while the third armportion and the first hand are overlapped in the up-down direction, andprotrude upwardly up to the height at which it does not touch themounting portion; the motor for the first hand and the motor for thesecond hand be respectively arranged inside the third arm portion suchthat the output shaft thereof faces down and part of them are locatedinside the protrusion portion. With this configuration, part of thefirst hand motor and the second hand motor can be positioned by usingthe protrusion portion protruding to the dead space created between themounting portion of the first hand and the third arm portion. Therefore,the entire thickness of the first hand, the second hand and the thirdarm portion in the up-down direction can be reduced.

In at least an embodiment of the present invention, it is preferred thatthe rotation mechanism be provided with a magnetic fluid seal arrangedaround the outer circumferential side of the Harmonic Drive (registeredtrade mark). With this configuration, dust generated at the HarmonicDrive (registered trade mark) can be prevented from coming to theoutside.

As described above, to achieve the above, it is possible in thehorizontal articulated robot of at least an embodiment of the presentinvention that the horizontal articulated robot can be installed suchthat the hand can make precise movements in the horizontal directionwith ease in a relatively short amount of time. Also, in the horizontalarticulated robot manufactured by the method for manufacturing ahorizontal articulated robot of at least an embodiment of the presentinvention, the horizontal articulated robot can be installed such thatthe hand can make precise movements in the horizontal direction withease in a short amount of time.

As described above, to achieve the above, in the horizontal articulatedrobot of at least an embodiment of the present invention having motorswhich are arranged in the arm portion configuring part of the arm suchthat the axial direction of their output shaft is in the horizontaldirection, the size of the motor can be reduced and backlash can bereduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, withreference to the accompanying drawings which are meant to be exemplary,not limiting, and wherein like elements are numbered alike in severalFigures, in which:

FIG. 1 A perspective view of a horizontal articulated robot of a firstembodiment of the present invention.

FIG. 2 A perspective view of the horizontal articulated robot of FIG. 1,showing that the arm is raised and extended.

FIG. 3 A plan view of a semiconductor manufacturing system in which thehorizontal articulated robot of FIG. 1 is used.

FIG. 4 A side view of the horizontal articulated robot of FIG. 1.

FIG. 5 A perspective view of a horizontal articulated robot of a secondembodiment.

FIG. 6 A perspective view of the horizontal articulated robot of FIG. 5,showing that the arm is raised and extended.

FIG. 7 A plan view of a semiconductor manufacturing system in which thehorizontal articulated robot of FIG. 5 is used.

FIG. 8 A side view of the horizontal articulated robot of FIG. 5.

FIG. 9 A cross-sectional view to explain the configuration of a rotationmechanism shown in FIG. 8.

DETAILED DESCRIPTION

A first embodiment is described referring to the drawing.

Configuration of Horizontal Articulated Robot

FIG. 1 is a perspective view of a horizontal articulated robot 1 of thefirst embodiment of the present invention. FIG. 2 is a perspective viewof the horizontal articulated robot 1 of FIG. 1, showing an arm 6 raisedand extended. FIG. 3 is a plan view of a semiconductor manufacturingsystem 9 in which the horizontal articulated robot 1 of FIG. 1 is used.FIG. 4 is a side view of the horizontal articulated robot of FIG. 1.

The horizontal articulated robot 1 of this embodiment is a robot fortransferring semiconductor wafers 2 which are objects-to-be-transferred(see FIG. 3). The horizontal articulated robot 1 is provided with twohands 4 and 5 on which semiconductor wafers are to be mounted, an arm 6to which the hands 4 and 5 are rotatably joined to the front end thereofand which moves in the horizontal direction, and a main body portion 7to which the base end of the arm 6 is rotatably joined. In the followingdescription, the horizontal articulated robot 1 is denoted as the “robot1” and the semiconductor wafer 2 as the “wafer 2”. Also, in thefollowing description, the X direction orthogonal to the up-downdirection in FIG. 1, etc. is the “left-right direction”; the Y directionorthogonal to the up-down direction and the left-right direction is the“front-rear direction; the X1 direction side is the “right” side; the X2direction side is the “left” side; the Y1 direction side is the “front”side; the Y2 direction side is the “rear” side.

As shown in FIG. 3, the robot 1 is installed and used in a semiconductormanufacturing system 9. The a semiconductor manufacturing system 9 isprovided with an EFEM 10 and a semiconductor wafer processing device 11which performs predetermined processes on wafers 2. The EFEM 10 ispositioned on the front side of the semiconductor wafer processingdevice 11. The robot 1 configures part of the EFEM 10. Also, the EFEM 10is provided with multiple load ports 13 for opening and closing FOUPs 12and a housing 14 in which the robot 1 is housed. The housing 14 isformed in a rectangular parallelepiped box shape elongated in theleft-right direction. The inside of the housing is kept as a cleanspace. In other words, the inside of the EFEM 10 is a clean space inwhich a predetermined cleanliness is maintained.

The FOUP 12 is manufactured based on the SEMI standard, in which 25 or13 individual wafers 2 can be stored, lying on top of another in theup-down direction. The load ports 13 are arranged on the front side ofthe housing 14. The EFEM 10 of this embodiment is provided with fourload ports 13 arranged at a predetermined pitch in the left-rightdirection, and four FOUPs 12 are arranged in the left-right direction ata predetermined pitch in the EFEM 10. The robot 1 transfers wafers 2between the four FOUPs 12 and the semiconductor wafer processing device11.

The arm 6 is configured by a first arm portion 16, of which the base endis rotatably joined to the main body portion 7, a second arm portion 17,of which the base end is rotatably joined to the front end of the firstarm portion 16, and a third arm portion, of which the base end isrotatably joined to the front end of the second arm portion 17. In otherwords, the arm 6 has three arm portions which are relatively rotatablyjoined to one another. The first arm portion 16, the second arm portion17 and the third arm portion 18 are formed hollow. Also, in thisembodiment, the length of the first arm portion 16, the length of thesecond arm portion 17, and the length of the third arm portion 18 arethe same. The main body portion 17, the first arm portion 16, the secondarm portion 17, and the third arm portion 18 are arranged in this orderfrom the bottom. The third arm portion 18 of this embodiment is ahand-side arm portion, and the second arm portion 17 is a secondhand-side arm portion.

The hands 4 and 5 are respectively formed such that the shape thereofwhen viewed in the up-down direction is a Y shape, and are respectivelyconfigured by a joint section 19 which is joined to the third armportion 18 and a wafer mounting portion 20 on which wafers 2 are to bemounted. The hands 4 and 5 are arranged to overlap in the up-downdirection. More specifically, the hand 4 is positioned at the top andthe hand 5 is positioned at the bottom. The hands 4 and 5 are positionedabove the third arm portion 18.

The joint section 19 configures the base end part of the hand 4, 5 andis rotatably joined to the front end of the third arm portion 18. Thewafer mounting portion 20 configures the front end portion of the hand4, 5 and is forked. The top surface of the wafer mounting portion 20 isa mounting-face 20 a on which wafers 2 are to be mounted. An adjustingbolt (no illustration in the figure) is attached to the joint betweenthe joint portion 19 and the third arm portion 18 to finely adjust theinclination of the mounting face 20 a with respect to the horizontaldirection. Also, a screw hole in which the adjusting bolt is screwed isformed in the joint of the joining portion 19 and the third arm portion18; the inclination of the mounting face 20 a is adjusted with respectto the horizontal direction by how much the adjusting bolt is screwedinto the screw hole.

Note that the illustration of the hand 5 is omitted in FIG. 3. Also, thehand 4 and the hand 5 sometimes overlap in the up-down direction duringthe operation of the robot 1 of this embodiment; however, most of thetime, the hand 4 and the 5 do not overlap in the up-down direction. Whenthe hand 4 is placed in the FOUP 12 as shown by long dashed double-shortline, for example, the hand 5 is rotated toward the main body portion 7and thus is not in the FOUP 12. The angle of rotation of the hand 5 withrespect to the hand 4 at that time is between 120° and 150°, forexample.

The main body portion 7 is provided with the housing 21 and a columnmember 22 (see FIG. 2) to which the base end of the first arm portion 16is rotatably joined. The housing 21 is formed in a rectangularparallelepiped shape elongated in the up-down direction, and the shapeof the housing 21 when viewed in the up-down direction is rectangular orsquare. The front face and the rear face of the housing 21 are parallelto the plane created by the up-down direction and the left-rightdirection; the left and right side faces of the housing 21 are parallelto the plane created by the up-down direction and the front-reardirection. Also, the bottom face of the housing 21 is formed to be aplanar orthogonal to the up-down direction.

The column member 22 is formed to be a column elongated in the up-downdirection. The base end of the first arm portion 16 is rotatably joinedto the top end of the column member 22. Housed inside the housing 21 isan arm-elevating mechanism (no illustration) for raising and loweringthe column member 22. In other words, housed inside the housing 21 is anarm-elevating mechanism for raising and lowering the first arm portion16 (that is, the arm 6) with respect to the main body portion 7. Thearm-elevating mechanism is configured by a ball screw positioned havingthe up-down direction as its axial direction, a nut member which engageswith the ball screw and a motor for rotating the ball screw. Thearm-elevating mechanism raises and lowers the arm 6 and the columnmember 22 between the position at which the column member 22 is storedinside the housing 21 as shown in FIG. 1 and the position at which thecolumn member 22 protrudes upwardly from the housing 21 as shown in FIG.2.

The column member 22 is positioned on the front side of the housing 21.Also, the column member 22 is positioned in the center of the housing 21in the left-right direction. A protrusion portion 21 a is formed on thetop of the housing 21, protruding upwardly. The protrusion portion 21 ais formed surrounding the left and right sides and the rear side of thecolumn member 22. The top surface of the protrusion portion 21 a isformed to be a flat plane orthogonal to the up-down direction. Also, atthe four corners at the bottom of the housing 21, a bolt mountingportion 21 b is formed to mount the adjusting bolt (no illustration)which finely adjusts the inclination of the entire robot 1 with respectto the horizontal direction. A screw hole in which the adjusting bolt isscrewed is formed in the bolt mounting portion 21 b such that it passesthrough in the up-down direction, and the inclination of the robot 1with respect to the horizontal direction is adjusted by the amount ofscrewing the adjusting bolt into the screw hole.

As shown in FIG. 1 and FIG. 2, a level 23 is attached to the top surfaceof the protrusion portion 21 a. In other words, the level 23 is attachedto the main body portion 7. The level 23 of this embodiment is a bubbletube-type level with a bubble tube. More specifically, the level 23 is aso-called bull's eye spirit level (a spirit level) having the bubbletube in a circular shape when viewed in the up-down direction and with acircular reference line printed at the center of the bubble tube whenviewed in the up-down direction. Note that the level 23 may be a bubbletube-type level other than a bull's eye spirit level, such as adual-axis level which is a combination of a single-axis-type bubble tubelevel that can check the inclination of one side in the horizontaldirection (for example, the left-right direction) and a single-axis-typebubble tube level that can check the inclination of the directionorthogonal to one side in the horizontal direction (for example, thefront-rear direction).

Also, the robot 1 is provided with an arm portion drive mechanism whichrotates the first arm portion 16 and the second arm portion 17 to extendand retract part of the arm 6 configured by the first arm portion 16 andthe second arm portion 17, a third arm drive mechanism which rotates thethird arm portion 18, a first hand-drive mechanism which rotates thehand 4 and a second hand-drive mechanism which rotates the hand 5.

As shown in FIG. 4, the arm portion drive mechanism is provided with amotor 125 as a driving source, a reduction gear 126 for reducing thepower of the motor 125 and transmitting the result to the first armportion 16, and a reduction gear 127 for reducing the power of the motor125 and transmitting the result to the second arm portion 17. The motor125 is arranged inside the housing 21. The reduction gear 126 configuresa joint section connecting the main body portion 7 and the first armportion 16. The reduction gear 127 configures a joint section connectingthe first arm portion 16 and the second arm portion 17. The reductiongears 126 and 127 are a harmonic drive (registered trade mark) which isa wave-motion gearing device, for example. In the same manner as thehorizontal articulated robot disclosed in the above-described Patentreference 1, the motor 125 and the reduction gear 126 are coupled witheach other via a pulley and a belt whose illustrations are omitted inthe figures, and the motor 125 and the reduction gear 127 are coupledvia a pulley and a belt whose illustrations are omitted in the figures.

The third arm portion drive mechanism, as shown in FIG. 4, is providedwith a motor 128 which is a driving source and a reduction gear 129 forreducing the power of the motor 128 and transmitting the result to thethird arm portion 18. The motor 28 is arranged inside the front end ofthe second arm portion 17. The reduction gear 129 configures a jointsection connecting the second arm portion 17 and the third arm portion18. The reduction gear 129 is a harmonic drive (registered trade mark),for example. The motor 128 and the reduction gear 129 are coupled via agear train whose illustration is omitted in the figures.

The first hand drive mechanism, as shown in FIG. 4, is provided with amotor 130 and a reduction gear 131 for reducing the power of the motor130 and transmitting the result to the hand 4. The second hand drivemechanism, in the same manner as the first hand drive mechanism, isprovided with a motor 132 and a reduction gear 133 for reducing thepower of the motor 132 and transmitting the result to the hand 5. Themotors 130 and 132 and the reduction gears 131 and 133 are arrangedinside the third arm portion 18. The reduction gears 131 and 133 are aharmonic drive (registered trade mark), for example. In the same manneras the horizontal articulated robot disclosed in the above-describedPatent reference 1, the reduction gear 131 is attached to the outputshaft of the motor 130, the reduction gear 133 is attached to the outputshaft of the motor 132. Also, the joining portion 19 of the hand 4 andthe reduction gear 131 are connected via a pulley and a belt whoseillustrations are omitted in the figures, and the joining portion 19 ofthe hand 5 and the reduction gear 133 are connected via a pulley and abelt whose illustrations are omitted in the figures.

In the process of manufacturing the robot 1, once the hands 4 and 5, thearm 6 and the main body portion 7 are assembled together to enable therobot 1 to move, the robot 1 is placed on a predetermined referencesurface where planarity is maintained. At this time, the level 23 is notattached to the main body portion 7 yet. Then, the inclination of thecenter axis of rotation of the third arm portion 18 with respect to thesecond arm portion 17 is adjusted with respect to the up-down direction(the vertical direction). Also, the inclination of the mounting face 20a of the hand 4, 5 is adjusted with respect to the horizontal direction.

More specifically, while changing the position of the robot 1 to variousstates, such as the state in which the arm 6 is extended in a certaindirection, the state in which the arm is extended in the otherdirection, and the state in which the arm 6 is retracted, theinclination of the entire robot 1 is adjusted by the adjusting boltattached to the bolt attaching portions 21 b in the housing 21 so thatthe center axis of rotation of the third arm portion 18 with respect tothe second arm portion 17 does not incline more than a predeterminedangle with respect to the vertical direction; in this way, theinclination of the center axis of rotation of the third arm portion 18with respect to the second arm portion 17 can be adjusted with respectto the vertical direction.

Also, while changing the position of the robot 1 to various states, theinclination of the mounting face 20 a with respect to the horizontaldirection is adjusted by the adjusting bolt attached to the joiningplace between the joining portion 19 and the third arm portion 18 sothat the inclination of the mounting face 20 a with respect to thehorizontal direction does not incline more than a predetermined anglewith respect to the horizontal direction no matter what state the robot1 is in. Note that the gap between the hand 4 and the hand 5 in theup-down direction is also adjusted.

When these adjustments are completed, the level 23 is attached to themain body portion 7. More specifically, the level 23 is secured to themain body portion 7 such that the bubble in the bubble tube of the level23 is contained within the reference line printed on the bubble tube.

Major Effects of the First Embodiment

As described above, in this embodiment, first the inclination of thecenter axis of rotation of the third arm portion 18 with respect to thesecond arm portion 17 is adjusted with respect to the vertical directionand the inclination of the mounting face 20 a of the hand 4, 5 isadjusted with respect to the horizontal direction, and then the level 23is attached to the main body portion 7 such that the bubble in thebubble tube of the level 23 is contained within the reference lineprinted on the bubble tube. Therefore, in this embodiment, at the timeof the installation of the robot 1 in the housing 14 of the EFEM 10, therobot 1 is positioned such that the bubble in the bubble tube of thelevel 23 is contained within the reference line; as a result, the robot1 can be installed such that the inclination of the center axis ofrotation of the third arm portion 18, to which the hands 4 and 5 arerotatably joined, with respect to the second arm portion 17 is adjustedto a proper inclination with respect to the vertical direction, and theinclination of the mounting face 20 a with respect to the horizontaldirection is adjusted to a proper inclination. Therefore, in thisembodiment, the robot 1 can be installed in the housing 14 such that thehands 4 and 5 can make precise movements in the horizontal directionwith ease in a short amount of time.

In the case in which the level 23 is attached to the hands 4 and 5 orthe arm 6, the bubble in the bubble tube of the level 23 easily changesits position depending on the extended or retracted position of the arm6; therefore, even if the robot 1 is positioned in the housing 14 suchthat the bubble is contained within the reference line, the robot 1 maynot be installed in the housing 14 to have the hands 4 and 5 makeprecise movements in the horizontal direction, depending on theextended/retracted state of the arm 6 at the installation. However, inthis embodiment, the level 23 is attached to the main body portion 7;therefore, the bubble in the bubble tube of the level 23 does not changeits position easily despite the extended/retracted state of the arm 6.Therefore, in this embodiment, by positioning the robot in the housing14 such that the bubble in the level 23 is contained within thereference line, the robot 1 can be installed in the housing 14 to havethe hands 4 and 5 make precise movements in the horizontal directiondespite the extended/retracted state of the arm 6 at the time ofinstallation.

Other Embodiments

The above-described first embodiment is an example of the preferredembodiment of the present invention; however, the embodiment is notlimited to this, but can be varyingly modified within the scope of theinvention.

In the above-described embodiment, first the inclination of the centeraxis of rotation of the third arm portion 18 with respect to the secondarm portion 17 is adjusted with respect to the vertical direction andthe inclination of the mounting face 20 a of the hand 4, 5 is adjustedwith respect to the horizontal direction, and then the level 23 isattached to the main body portion 7 such that the bubble in the bubbletube of the level 23 can be contained within the reference line printedon the bubble tube. Beside this, under the condition where theinclination of the center axis of rotation of the third arm portion 18with respect to the second arm portion 17 is adjusted with respect tothe vertical direction but the inclination of the mounting face 20 a isnot adjusted with respect to the horizontal direction, the level 23 maybe attached to the main body portion 7 such that the bubble in thebubble tube of the level 23 is contained within the reference lineprinted on the bubble tube. Once the inclination of the center axis ofrotation of the third arm portion 18 with respect to the second armportion 17 is adjusted with respect to the vertical direction, theinclination of the hand 4, 5 with respect to the horizontal directioncan be controlled; therefore, even in this case, by positioning therobot 1 in the housing 14 such that the bubble in the bubble tube of thelevel 23 is contained within the reference line, the robot 1 can beinstalled in the housing 14 to have the hands 4 and 5 make precisemovements in the horizontal direction.

In the above-described embodiment, the level 23 is attached to the mainbody portion 7. Beside this, the level 23 may be attached to the arm 6or the hand 4 or the hand 5. Also, in the above-described embodiment,the level 23 is a bubble tube-type level; however, the level 23 may be alazar level or a digital level other than a bubble tube-type level.

In the above-described embodiment, the main body portion 7 is formed ina rectangular parallelepiped shape elongated in the up-down direction;however, the main body portion 7 may be formed in a columnar shape or ina polygonal columnar shape having a hexagonal or octagonal shape whenviewed in the up-down direction. Also, in the above-describedembodiment, the two hands 4 and 5 are attached to the front end of thethird arm portion 18; however, one hand may be attached to the front endof the third arm portion 18. Also, in the above-described embodiment,the arm 6 is configured by three arm portions which are the first armportion 16, the second arm portion 17 and the third arm portion 18;however, the arm 6 may be configured by two arm portions or four or morearm portions.

In the above-described embodiment, the semiconductor wafer processingapparatus 11 is positioned on the rear side of the EFEM 10 in thesemiconductor manufacturing system 9. Beside this, the semiconductorwafer processing apparatus 11 may be arranged on the right side, leftside or both sides of the EFEM 10. For example, as shown by long dasheddouble-short line in FIG. 3, the semiconductor wafer processingapparatus 11 may be positioned on the right side of the EFEM 10. Also,in the above-described embodiment, the robot 1 is a robot fortransferring wafers 2; however, the robot 1 may be a robot fortransferring other objects-to-be-transferred such as liquid crystalglass substrates.

Second Embodiment

The second embodiment of the present invention is hereinafter describedreferring to the drawing.

Entire Configuration of Horizontal Articulated Robot

FIG. 5 is a perspective view of a horizontal articulated robot 1 of thesecond embodiment of the present invention. FIG. 6 is a perspective viewof the horizontal articulated robot 1 of FIG. 5 with the arm 6 elevatedand extended. FIG. 7 is a plan view of a semiconductor manufacturingsystem 9 in which the horizontal articulated robot 1 of FIG. 5 is used.FIG. 8 is a side view of the horizontal articulated robot 1 of FIG. 5.Note that the same codes are given to the same components as theabove-described first embodiment.

The horizontal articulated robot 1 of the second embodiment is a robotfor transferring semiconductor wafers 2 which areobjects-to-be-transferred (see FIG. 7). This horizontal articulatedrobot 1 is provided with two hands 4 and 5 on which semiconductor wafers2 are to be mounted, an arm 6 to which the front end of the hands 4 and5 are rotatably joined and which moves in the horizontal direction, anda main body portion 7 to which the base end of the arm 6 is rotatablyjoined. In the following description, the horizontal articulated robot 1is denoted as a “robot 1” and the semiconductor wafer 2 a “wafer 2”.Also, in the following description, the X direction in FIG. 5 which isorthogonal to the up-down direction is the left-right direction“, the Ydirection which is orthogonal to the up-down direction and theleft-right direction is the front-rear direction”, the X1 direction sideis the “right” side, the X2 direction side the “left” side, the Y1direction side the “front” side and the Y2 direction side the “rear”side.

As shown in FIG. 7, the robot 1 is installed and used in thesemiconductor manufacturing system 9. The semiconductor manufacturingsystem 9 is provided with the EFEM 10 and the semiconductor waferprocessing apparatus 1 for performing predetermined process on wafers 2.The EFEM 10 is positioned on the front side of the semiconductor waferprocessing apparatus 11. The robot 1 configures part of the EFEM 10.Also, the EFEM 10 is provided with multiple load ports 13 for openingand closing the FOUPs 12 and a housing 14 in which the robot 1 s housed.The housing 14 is formed in a rectangular parallelepiped box shapeelongated in the left-right direction. The inside of the housing 14 is aclean space. In other words, the inside of the EFEM 10 is a clean spacein which predetermined cleanliness is maintained.

The FOUP 12 is manufactured based on the SEMI standard and 25 or 13individual wafers 2 can be stored. The load ports 13 are arranged on thefront side of the housing 14. The EFEM 10 of this embodiment is providedwith four load ports 13 arranged at a predetermined pitch in theleft-right direction, and four FOUPs 12 are arranged at a predeterminedpitch in the left-right direction in the EFEM 10. The robot 1 transferswafers 2 between the four FOUPs 12 and the semiconductor waferprocessing apparatus 11.

The arm 6 is configured by a first arm portion, of which the base end isrotatably joined to the main body portion 7, a second arm portion 17, ofwhich the base end is rotatably joined to the front end of the first armportion 16, and a third arm portion 18, of which the base end isrotatably joined to the front end of the second arm portion 17. In otherwords, the arm 6 has three arm portions which are relatively rotatablyjoined to one another. The first arm portion 16, the second arm portion17 and the third arm portion 18 are formed hollow. Also, in thisembodiment, the length of the first arm portion 16, the length of thesecond arm portion 17 and the length of the third arm portion are thesame. The main body portion 7, the first arm portion 16, the second armportion 17 and the third arm portion 18 are positioned in this orderfrom the bottom. The second arm portion 17 of this embodiment is asupporting arm portion, and the third arm portion 18 is a supported armportion.

The hands 4 and 5 are formed to have a Y shape when viewed in theup-down direction, and are respectively configured by a joining portion19 joined to the third arm portion 18 and a mounting portion on whichwafers 2 are to be mounted. The hands 4 and 5 are arranged such that thejoining portion 19 of the hand 4 and the joining portion 19 of the hand5 overlap with each other in the up-down direction. More specificallydescribed, the hand 4 is positioned at the top and the hand 5 ispositioned at the bottom. Also, the hands 4 and 5 are arranged above thethird arm portion 18. The hand 5 of this embodiment is the first hand,and the hand 4 is the second hand.

The joining portion 19 configures the base end portion of the hands 4and 5 and is rotatably joined to the front end of the third arm portion18. The mounting portion 20, configuring the front end portion of thehands 4 and 5, is forked. Also, the mounting portion 20 is formed to beflat. As shown in FIG. 8, the mounting portion 20 of the hand 4 isformed extending from the bottom end of the joining portion 19 in thehorizontal direction, and the mounting portion 20 of the hand 5 isformed extending from the top end of the joining portion 19 in thehorizontal direction. The top surface of the mounting portion 20 is amounting face on which wafers 2 are to be mounted.

Note that the illustration of the hand 5 is omitted in FIG. 7. Also, atthe time of operation of the robot 1 of this embodiment, the hand 4 andthe hand 5 sometimes overlap in the up-down direction; however, most ofthe time, the hand 4 and the hand 5 do not overlap in the up-downdirection. For example, as shown by long dashed double-short line inFIG. 7, when the hand 4 is placed in the FOUP 12, the hand 5 is rotatedtoward the main body portion 7, not being in the FOUP 12. The angle ofrotation of the hand 5 with respect to the hand 4 at that time isbetween 120° and 150°.

Also, a protruding portion 18 a is formed to the third arm portion 18,protruding upwardly. As shown in FIG. 8, the protruding portion 18 a isformed at the position which is shifted from the joining portion 19 ofthe hand 5 in the longitudinal direction of the third arm portion 18 (inthe front-rear direction in the state shown by FIG. 8) so that it doesnot touch the joining portion 19 of the hand 5 when the third armportion 18 and the hand 5 are overlapped in the up-down direction. Also,the protruding portion 18 a protrudes upwardly to the height at which itdoes not touch the mounting portion 20.

The main body portion 7 is provided with a housing 21 and a columnmember 22 (see FIG. 6), to which the base end of the first arm portion16 is rotatably joined. The housing 21 is formed to be rectangularparallelepiped shape elongated in the up-down direction, with arectangular or square shape when viewed in the up-down direction. Also,the front face and the rear face of the housing 21 are parallel to theplane created by the up-down direction and the left-right direction; theright and left side faces of the housing 21 is parallel to the planecreated by the up-down direction and the front-rear direction.

The column member 22 is formed to be a thin column elongated in theup-down direction. The base end of the first arm portion 16 is rotatablyjoined to the top end of the column member 22. Housed inside the housing21 is an arm-elevating mechanism (no illustration) for raising andlowering the column member 22. In other words, housed inside the housing21 is an arm-elevating mechanism for raising and lowering the first armportion 16 (that is, the arm 6) with respect to the main body portion 7.The arm-elevating mechanism is configured by a ball screw, which isarranged having the up-down direction as its axial direction, a nutmember which engages with the ball screw, and a motor for rotating theball screw. The arm-elevating mechanism raises and lowers the arm 6 andthe column member 22 between the position at which the column member ishoused in the housing 21, as shown in FIG. 5, and the position at whichthe column member 22 protrudes upwardly from the housing 21, as shown inFIG. 6. The column member 22 is arranged on the front side of thehousing 21. Also, the column member 22 is positioned in the center ofthe housing 21 in the left-right direction.

The robot 1 is also provided with an arm portion-driving mechanism 25which rotates the first arm portion 16 and the second arm portion 17 toextend and retract part of the arm 6, which is configured by the firstarm portion 16 and the second arm portion 17, a third arm portionrotating mechanism 26 as a rotating mechanism for rotating the third armportion 18 with respect to the second arm portion 17, a firsthand-rotating mechanism 27 for rotating the hand 5 with respect to thethird arm portion 18, and a second hand-rotating mechanism 28 forrotating the hand 4 with respect to the third arm portion 18.

As shown in FIG. 8, the arm portion-driving mechanism 25 is providedwith a motor 30 which is a driving source, a reduction gear 31 forreducing the power of the motor 30 and transmitting the result to thefirst arm portion 16, and a reduction gear 32 for reducing the power ofthe motor 30 and transmitting the result to the second arm portion 17.The motor 30 is arranged inside the housing 21. The reduction gear 31configures a joint section that joins the main body portion 7 and thefirst arm portion 16. The reduction gear 32 configures a joint sectionthat joins the first arm portion 16 and the second arm portion 17. Thereduction gear 31, 32 is a harmonic drive (registered trade mark) whichis a wave-motion gearing device, for example. In the same manner as theindustrial robot disclosed in the above-described Unexamined JapanesePatent Application Publication 2011-230256, the motor 30 and thereduction gear 31 are connected with each other via a pulley and a beltwhose illustrations are omitted in the figure. Also, the motor 30 andthe reduction gear 32 are connected with each other via a pulley and abelt whose illustrations are omitted in the figure, in the same manneras the industrial robot disclosed in the above-described UnexaminedJapanese Patent Application Publication 2011-230256.

The third arm portion-driving mechanism 27, as shown in FIG. 8, isprovided with a motor 35 which is a driving source and a reduction gear36 for reducing the power of the motor 28 and transmitting the result tothe third arm portion 18. The more detailed configuration of the thirdarm portion-rotating mechanism 26 is described later.

The first hand-rotating mechanism 27, as shown in FIG. 8, is providedwith a motor 35 which is a driving source, and a reduction gear 36 forreducing the power of the motor 35 and transmitting the result to thehand 5. In the same manner as the first hand-rotating mechanism 27, thesecond hand-rotating mechanism 28 is provided with a motor 37 which is adriving source and a reduction gear 38 for reducing the power of themotor 37 and transmitting the result to the hand 4. The motor 35 of thisembodiment is the motor for the first hand, and the motor 37 is themotor for the second hand.

The motors 35, 37 and the reduction gears 36, 38 are arranged inside thethird arm portion 18. Also, the motors 35 and 37 are each respectivelyarranged inside the third arm portion 18 such that its output shaftfaces down and part of its counter-output shaft is placed in theprotruding portion 18 a of the third arm portion 18. The reduction gears36 and 38 are a harmonic drive (registered trade mark), for example. Thereduction gear 36 is attached to the output shaft of the motor 35protruding downwardly, and the reduction gear 38 is attached to theoutput shaft of the motor 37 protruding downwardly. In the same manneras the horizontal articulated robot disclosed in the Unexamined JapanesePatent Application Publication 2011-230256, the joining portion 19 ofthe hand 5 and the reduction gear 36 are connected to each other via apulley and a belt whose illustrations are omitted in the figure, and thejoining portion 19 of the hand 4 and the reduction gear 36 are connectedto each other via a pulley and a belt whose illustrations are omitted inthe figure.

Configuration of Third Arm Portion-Rotating Mechanism

FIG. 9 is a cross-sectional view to explain the configuration of thethird arm portion-rotating mechanism 26 shown in FIG. 8.

The third arm portion-rotating mechanism 26 is provided with the motor33 and the reduction gear 34 as described above. The motor 33 isarranged inside the second arm portion 17. The motor 33 is also securedinside the second arm portion 17 such that the axial direction of itsoutput shaft is parallel to the horizontal direction. More specifically,the motor 33 is secured inside the second arm portion 17 such that itsoutput shaft protrudes toward the front end of the second arm portion17.

One end of the rotating shaft 42 is coupled with the output shaft of themotor 33 via a coupling. The rotating shaft 42 is arranged inside thesecond arm portion 17 such that its axial direction coincides with thehorizontal direction. In other words, a bevel gear 43 is coupled withthe output shaft of the motor 33 via the coupling 41 and the rotatingshaft 42. Also, the other end of the rotating shaft 42 is rotatably heldby a bearing which is secured inside the second arm portion 17.

The reduction gear 34 configures a joint section connecting the secondarm portion 17 and the third arm portion 18. In other words, thereduction gear 34 configures a joint section which is a joining portionbetween the second arm portion 17 and the third arm portion 18. Thereduction 34 is arranged having its axial direction in the up-downdirection. The reduction gear 34 also is a harmonic drive (registeredtrade mark), and as shown in FIG. 5, is configured by a wave generator45, a circular spline 46 and a flex spline 47. The flex spline 47 issecured to the base end of the third arm portion 18 via a frame 48. Thecircular spline 46 is fixed to the front end of the second arm portion17 via a frame 49. A bevel gear 50 as a second bevel gear is secured tothe bottom end of the wave generator 45. In other words, the bevel gear50 is secured to the bottom end of the wave generator 45. The bevel gear50 meshes with a bevel gear 34.

On the outer circumferential side of the gear 34, a magnetic fluid seal51 is arranged to prevent dust generated at the reduction gear 34 fromgoing outside of the second arm portion 17 and the third arm portion 18.Also, a hollow shaft 52 arranged to pass through the center of thereduction gear 34 is secured on the base end side of the third armportion 18. The wave generator 45 is rotatably arranged at the outercircumferential side of the hollow shaft 52. Note that a predeterminedwiring is done, utilizing the inner circumference side of the hollowshaft 52.

Major Effects of this Second Embodiment

As described above, in the second embodiment of the present invention,the power of the motor 33 is reduced by the reduction gear 34, which isa harmonic drive (registered trade mark), and transmitted to the thirdarm portion 18. Therefore, in this embodiment, the reduction ratio canbe increased in the power-transmitting path from the motor 33 to thethird arm portion 18. Therefore, in this embodiment, even when the motor33 uses a motor with small output, the third arm portion 18 can berotated with respect to the second arm portion; as a result, the size ofthe motor 33 can be reduced. Further, in this embodiment, the power ofthe motor 33 is reduced and transmitted to the third arm portion 18 bythe reduction gear 34 which is a harmonic drive (registered trade mark);therefore, backlash can be reduced in the power-transmitting path fromthe motor 33 to the third arm portion 18.

In the second embodiment, the protruding portion 18 a protrudingupwardly is formed to the third arm portion 18. This protruding portion18 a is formed at the position which is shifted from the joining portion19 of the hand 5 in the longitudinal direction of the third arm portion18 and also protrudes upwardly to the height at which it is kept fromtouching the mounting portion 20 of the hand 5. Also, in thisembodiment, the motor 35, 37 is arranged inside the third arm portion 18such that its output shaft faces down and part of its counter-outputshaft of the motor 35, 37 is placed in the protruding portion 18 a.Therefore, in this embodiment, part of the motor 35, 37 can bepositioned, utilizing the protruding portion 18 a protruding into thedead space between the mounting portion 20 of the hand 5 and the thirdarm portion 18 in the up-down direction. Accordingly, in thisembodiment, the thickness of the hands 4 and 5 and the third arm portion18 altogether in the up-down direction can be reduced.

Other Embodiment

In the above-described second embodiment is an example of the preferredembodiment of the present invention; however, it is not limited to this,but can be varyingly modified within the scope of the invention.

In the above-described embodiment, the motor 33 is arranged inside thesecond arm portion 17; however, the motor 33 may be arranged inside thethird arm portion 18. In this case, the circular spline 46 is secured onthe base end side of the third arm portion 18 via the frame 49, and theflex spline 47 is secured on the base end side of the third arm portion18 via the frame 48. Also, in this case, the power of the motor 33 isreduced by the reduction gear 34 and transmitted to the second armportion 17.

In the above-described embodiment, the arm 6 is configured by three armportions which are the first arm portion 16, the second arm portion 17and the third arm portion 18; however, the arm 6 may be configured bytwo arm portions or by four or more arm portions. Also, two hands 4 and5 are attached on the front end side of the third arm portion 18 in theabove-described embodiment; however, only one hand may be attached onthe front end side of the third arm portion 18.

In the above-described embodiment, the semiconductor wafer processingapparatus 11 is arranged on the rear side of the EFEM 10 in thesemiconductor manufacturing system 9. Beside this, the semiconductorwafer processing apparatus 11 may be positioned on the ride side, theleft side or both sides of the EFEM 10. For example, as shown by longdashed double-short line in FIG. 3, the semiconductor wafer processingapparatus 11 may be positioned on the right side of the EFEM 10. Also,in the above-described embodiment, the robot 1 is a robot fortransferring wafers 2; however, the robot 1 may be a robot fortransferring other type of objects-to-be-transferred such as liquidcrystal glass substrates.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

The presently disclosed embodiments are therefore to be considered inall respects as illustrative and not restrictive, the scope of theinvention being indicated by the appended claims, rather than theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedtherein.

What is claimed is:
 1. A horizontal articulated robot in which an armmoves in the horizontal direction for use with objects to betransferred, comprising: a hand on which the objects are to be mounted;said arm having at least two arm portion, comprising: a hand-side armportion to which said hand is rotatably joined to the front end thereofand a second hand-side arm portion to which the base end of saidhand-side arm portion is rotatably joined to the front end thereof; anda main body portion to which the base end of said arm is rotatablyjoined; and a level which is attached to said main body portion after aninclination of a center axis of rotation of said hand-side arm portionwith respect to said second hand-side arm portion is adjusted relativeto the vertical direction; wherein said level is directly attached tosaid main body portion so as to be fixed relative to said main bodyportion.
 2. The horizontal articulated robot as set forth in claim 1wherein a mounting face on which said objects-to-be-transferred are tobe mounted is formed on said hand; and said level is attached after theinclination of said mounting face is adjusted with respect to thehorizontal direction.
 3. The horizontal articulated robot as set forthin claim 1 wherein said level is a bubble tube-type level having abubble tube and is attached after the inclination of the center axis ofrotation of said hand-side arm portion with respect to said secondhand-side arm portion is adjusted relative to the vertical direction sothat a bubble inside said bubble tube is contained within a referenceline printed on said bubble tube.
 4. A method for manufacturing ahorizontal articulated robot which comprises a hand on whichobjects-to-be-transferred are to be mounted, an arm having at least twoarm portions, namely, a hand-side arm portion to which said hand isrotatably joined to the front end thereof and a second hand-side armportion to which the base end of said hand-side arm portion is rotatablyjoined to the front end thereof, a main body portion to which the baseend of said arm is rotatably joined, and a level which is attached tosaid hand, said arm or said main body portion; the method comprising:adjusting an inclination of a center axis of rotation of said hand-sidearm portion with respect to said second hand-side arm portion relativeto the vertical direction; and attaching said level after at leastadjusting the inclination of the center axis of rotation of saidhand-side arm portion with respect to said second hand-side arm portionrelative to the vertical direction; wherein said level is directlyattached to said main body portion so as to be fixed relative to saidmain body portion.